JPH07180559A - Spark ignition internal combustion engine - Google Patents

Abstract

(57) [Summary] [Purpose] To improve the stability of spark-ignition internal combustion gold during lean air-fuel ratio operation. [Structure] In a spark ignition type internal combustion engine in which an air-fuel ratio is diluted according to operating conditions, a tumble ratio of intake air flow in a cylinder is 1.6 to 3.1 and a swirl ratio is 1.8 when the lean air-fuel ratio is operating. Set the intake system so that it becomes ~ 3.5. Further, as means for realizing such a tumble swirl ratio, the intake pipe 7 is made equal in length and symmetrical between the cylinders, an air control valve 11 having an opening 13 at a predetermined position is provided, and this air control is performed. The upper part of the valve 11 is attached to the downstream side while being inclined by a predetermined angle, the intake port 6 is formed in a tumble strengthening port shape that causes a vertical vortex in the cylinder, and the intake valve 15 on the air control valve opening 13 side is It is proposed to provide two intake valves 14 and 15 that are opened and driven with a phase difference so as to open early.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a spark ignition type internal combustion engine which leans the air-fuel ratio according to operating conditions.

[0002]

2. Description of the Related Art In a spark ignition type internal combustion engine, a swirl control valve provided with a partial opening such as a notch for the purpose of improving combustion characteristics mainly at low load operation or lean air-fuel ratio operation ( An air control valve called SCV) is provided in the vicinity of the engine intake port, and the intake flow is concentrated at the opening of the engine to bias the intake air in the passage and increase the flow velocity to promote the air flow in the cylinder. Things are known (for example, actual Kaihei 1-9
1038 gazette).

[0003]

By the way, in such a conventional internal combustion engine, generally, the length of the branch pipe of the intake manifold and the shape of the intake passage upstream of the air control valve are different for each cylinder, and Is due to the lack of vertical vortex (tumble) in the cylinder, and due to the error in the air control valve mounting and notch shape of each cylinder, the average flow velocity of intake air for each cycle tends to fluctuate. However, there has been a problem that a stable lean burn operation cannot always be performed, or the air-fuel ratio for obtaining a stable operating state cannot be sufficiently increased, and the lean burn limit is low.

An object of the present invention is to eliminate such a conventional problem.

[0005]

In order to achieve the above object, according to the present invention, in a spark ignition type internal combustion engine in which an air-fuel ratio is diluted according to operating conditions, a tumble of intake air flow in a cylinder during lean air-fuel ratio operation. The present invention proposes an internal combustion engine in which an intake system is set so that the ratio is 1.6 to 3.1 and the swirl ratio is 1.8 to 3.5.

However, tumble ratio = rotational speed of vertical vortex in cylinder / engine rotational speed Swirl ratio = rotational speed of horizontal vortex in cylinder / engine rotational speed

Further, the present invention proposes a spark ignition type internal combustion engine which is individually provided with or combined with the following means A to E as a structure for obtaining such a tumble ratio and a swirl ratio.

A. Arranging a plurality of intake pipes branching from the intake collector collecting portion and reaching the intake ports of the engine in equal length and symmetrically in the cylinder row direction.

B. An air control valve having a partial opening is provided in the intake passage near the intake port. However, it is desirable that the air control valve further includes the following configuration a or b.

A. In the lean air-fuel ratio operation, the opening side should be set to a predetermined amount downstream in a closed state, preferably within a range of 20 to 30 degrees with respect to a cross section perpendicular to the central axis of the intake passage.

B. The opening is formed in a portion that is above the substantially horizontal mounting shaft and is deviated to one side, and it is preferable that the angle formed by the mounting axis center line of the line segment connecting the center of gravity (centroid) of the opening and the passage center. Form it to be in the range of 45 to 75 degrees upward.

C. The shape of the intake passage immediately upstream of the air control valve is made substantially the same among the cylinders, and the length thereof is preferably set within a range of 1.5 to 3.5 times the inner diameter of the intake port.

D. Form each intake port into a shape that causes vertical vortices in the cylinder, and in particular, form a straight line with a small angle between the intake port centerline and the horizontal plane.

E. Two intake valves that are driven to open with a phase difference so that the intake valve on the air control valve opening side opens early.

On the premise of a spark ignition type internal combustion engine in which the air-fuel ratio is diluted according to operating conditions, the first recommended specific combination of each of these means is to branch from the intake collector collecting portion. A plurality of intake pipes that reach each intake port of the engine are arranged in a symmetrical shape in the cylinder row direction with equal length to each other, and partially have an opening, and the opening is downstream in a closed state during lean air-fuel ratio operation. An air control valve that is controlled to incline by a predetermined amount is installed near each intake port, and the shape of the intake passage immediately upstream of the air control valve is made substantially the same for each cylinder, and each intake port is To form a vertical vortex in the cylinder.

Secondly, a plurality of intake pipes branching from the intake collector collecting portion and reaching each intake port of the engine are arranged in equal length and symmetrically in the cylinder row direction, and the opening portions are partially formed. An air control valve, which is controlled so that the opening inclines toward the downstream side by a predetermined amount in the closed state during lean air-fuel ratio operation, is provided near each intake port, and the intake passage immediately upstream of the air control valve is provided. The cylinders have substantially the same shape, and the intake ports are formed in a shape that causes vertical vortices in the cylinders. The tumble ratio is 1.6 to 3.1 and the swirl ratio is 1.8 to 3 during lean air-fuel ratio operation. It is necessary to set it to be 0.5.

Thirdly, it is provided with an intake port having a shape which causes a vertical vortex in the cylinder, and an air control valve which is interposed in the intake passage and has an opening formed partially.

Fourthly, an intake port having a shape that causes a vertical vortex in the cylinder and an opening formed in a portion which is interposed in the intake passage and is above the substantially horizontal mounting shaft and is biased to one side. The air control valve is set so that the opening side inclines toward the downstream side by a predetermined amount in the closed state during lean air-fuel ratio operation.

Fifthly, an opening is partially formed, and at the time of lean air-fuel ratio operation, the opening is provided with an air control valve which is set to incline toward the downstream side by a predetermined amount in the closed state, and the opening is provided. The section is formed such that the line segment connecting the center of gravity of the section and the center of the passage is at an angle of 60 to 70 degrees upward with the center line of the mounting axis, and the section on the air control valve opening side is early. It is provided with two intake valves that are driven to open with a phase difference so as to open.

According to the present invention, by providing such a configuration, an optimum air flow field is formed in the cylinder, and lean air-fuel ratio operation in a larger air-fuel ratio range can be performed without impairing combustion stability. It will be possible.

The operation and effects of the present invention will be described below together with the experimental results of the examples. In the following description and drawings, the air control valve is represented by "SCV" which is an abbreviation for a swirl control valve, and the tumble ratio and the swirl ratio are collectively referred to as "tumble swirl ratio".
I will call it.

[0022]

1 to 3 show an embodiment of a spark ignition type internal combustion engine according to the present invention. In each figure, 1 is an engine body, 2 is a cylinder, 3 is a cylinder head, 4 is a combustion chamber, 5 is a spark plug, 6 is an intake port, and 7 is an intake manifold.

As shown in FIG. 3, the intake manifold 7 has a plurality of intake pipes 9 that branch from the intake collector collecting portion 8 and reach each intake port 6 of the engine 1 and have a symmetrical shape in the cylinder row direction. It is located at.

A passage adapter 10 for forming a linear intake passage of the same shape between the cylinders is provided in the vicinity of the joint between each intake pipe 9 and the cylinder head 3, and an air adapter is provided in the portion near the intake port 6 thereof. The control valve 11 is interposed.

The air control valve 11 is rotatably supported by a mounting shaft 12 provided substantially horizontally so as to traverse the passage adapter 10, and is in a closed position during lean air-fuel ratio operation via an actuator (not shown). (State shown).

The air control valve 11 is partially formed with an opening 13 as shown in FIG. In this case, the opening 13 is formed in such a manner that a portion that is located above the mounting shaft 12 and is biased to one side is cut out.

The air control valve 11 in the closed position is set so that the opening 13 side is inclined downstream by a predetermined amount (α) as shown in FIG.

In this case, the intake port 6 is 2 in the cylinder row direction.
It branches from the middle so as to correspond to the intake valves 14 and 15 provided individually. Further, as a port shape for generating a strong vertical vortex, as shown in FIG. 2, the angle (θ) formed by the center line and the horizontal plane is small (θ = 10 to 30 degrees).
It is set.

In the present invention, for example, by constructing the spark ignition type internal combustion engine as described above, during lean air-fuel ratio operation,
The tumble ratio of the intake air flow in the cylinder is 1.6 to 3.1, and the swirl ratio is 1.8 to 3.5.

The characteristic of the tumble, that is, the port shape for strengthening the vertical vortex in the cylinder is that it has a linear shape and that the angle (θ) formed by the center line of the passage with the horizontal plane is small. That is, the vertical air downflow immediately below the intake valve on the cylinder center side in the first half of the intake stroke is suppressed as much as possible so as not to interfere with the generation of vertical vortices in the cylinder, and the air mass flow rate above the port is increased. The strength of the tumble increases. For example, in a certain type of internal combustion engine for small vehicles, it is effective to generate the tumble that the θ is about 10 to 30 degrees and the radius R of the curved portion on the downstream side is 50 mm or more.

FIG. 4 shows the result of studying the combustion stability during lean combustion by changing the length of the intake pipe (branch) of the intake manifold and the length L immediately upstream of the SCV (see FIG. 1) at a predetermined ratio. It is shown. The longer the intake pipe, the smaller the relative difference in intake pipe length between the cylinders.
As can be seen from the figure, the smaller the difference in the intake pipe length between the cylinders, the better the combustion stability during lean combustion. That is, it is a desirable condition for the intake manifold that the intake pipe has the same length for each cylinder to obtain stable combustibility under a lean air-fuel ratio.

Further, in FIG. 4, the length of the linear portion immediately upstream of the SCV is about 100 mm, and the combustion stability is the best. This corresponds to a length of about 2.5 times the inner diameter of the port. In practice, if the length is 1.5 to 3.5 times the inner diameter of the port, the effect of improving the stability during lean combustion can be obtained. This is because the difference in the air flow for each cylinder is smoothed in the straight part immediately upstream of the SCV, and the air flow field for each cylinder becomes uniform.

As described above, regarding the intake system, the intake pipes to the respective cylinders of the intake manifold are made equal in length, and particularly preferably, a length of 1.5 to 3.5 times the inner diameter of the port is provided immediately upstream of the SCV. By providing the intake passage portions having substantially the same shape, the air flow is made uniform among the cylinders, and specifically, the combustion stability limit air-fuel ratio value is about 1 to 1.5 (about 5% as a ratio) or more. The effect of increasing the combustion stability of the engine during lean combustion can be expected.

FIG. 5 shows the results of investigating the air-fuel ratio which becomes the stable combustion limit in the lean combustion by changing the opening position of the SCV variously. From this figure, there are optimum values for the tumble ratio indicating the strength of the vertical vortex and the swirl ratio indicating the strength of the horizontal vortex, respectively. Normally, the tumble ratio is 1.6 to 2.2 and the swirl ratio is 1. It can be seen that the range of 8 to 3.2 is optimal. However, increasing the output of the ignition system reduces the chances of ignition failure, so the tumble ratio is 2.2 to 3.1, and the swirl ratio is 1.8 to 3.5. Expanded.

In detail, when the tumble ratio is strong, turbulence is generated greatly, and the generation of this turbulence greatly affects the stability at the time of lean combustion. Therefore, the same combustion stability is exhibited as shown in FIG. The line is almost horizontal. On the other hand, when the tumble ratio becomes large, the fluctuation of the average flow velocity for each cycle becomes large for the same turbulence intensity as shown in FIG. When the fluctuation of the average flow velocity for each cycle becomes large, the air-fuel ratio, which is the combustion stability limit, moves in the rich direction as shown in FIG. 7. As shown in the figure, in the MPi method of injecting fuel into each intake port, compared with the SPi method of collectively supplying fuel for each cylinder from the upstream side of the manifold assembly, It is strongly influenced by cycle-to-cycle variations and it is therefore more important to suppress it. Further, when operating with the same air-fuel ratio, the combustion stability becomes worse as the tumble ratio relatively increases. From these, it can be seen that the horizontal vortex in the cylinder compensates for the drawback that the vertical vortex has a large variation in the average flow velocity in each cycle, and has the effect of suppressing the variation in the air flow field in each cycle. .

FIG. 8 shows an optimum tumble swirl region based on such knowledge. From this figure, the tumble ratio is 1.6 to 2.8, and the swirl ratio is 1.8 to 3.2.
It can be seen that there is an optimum value in the range. However, the results shown in FIGS. 5 and 8 are obtained under the condition that the ignition system is not specially strengthened. Practically, by using the ignition system which is further strengthened, the air-fuel ratio which becomes the stable combustion limit becomes large. Combustion is stable even if the tumble ratio and swirl ratio are slightly large.

Strengthening the ignition system means increasing the discharge period of the discharge voltage and increasing the discharge energy. For that purpose, it is generally necessary to improve the ignition coil and improve the durability of the ignition plug to withstand a large amount of discharge energy. However, excessive reinforcement of the ignition system consumes engine power for driving energy of the ignition coil, which leads to deterioration of fuel efficiency and consumption of the ignition plug. Therefore, there is a certain limit to the reinforcement of the ignition system.

FIG. 9 shows the stable combustion limits with respect to the tumble ratio and swirl ratio in the ignition system reinforced at a practically acceptable level. Optimum with tumble ratio = 2.7 and swirl ratio = 2.7. As described above, the tumble ratio is 2.2 to 3.1 and the swirl ratio is 1.8 to 3.5.
A combustion improving effect can be seen within the range.

Next, the influence of the position of the center of gravity of the SCV opening on the combustion stability will be described. FIG. 10 shows the relationship between the position of the center of gravity of the SCV opening and the stable combustion limit air-fuel ratio during lean combustion. There is an optimum value for the position of the center of gravity of the SCV opening, and assuming that an effect of approximately 95% of the optimum value is obtained in consideration of manufacturing errors and differences in engine specifications, the center of the passage will be moved to the center of gravity of the opening. The angle (β) formed by the drawn line segment with the mounting axis must be within the range of 45 to 70 degrees, and preferably β = 50 to 55 degrees. By combining this opening configuration and the intake port (tumble strengthening port) that causes the above-mentioned tumble, it becomes possible to obtain the optimum values of the above-mentioned tumble ratio = 2.7 and swirl ratio = 2.7.

It is possible to generate a tumble only with an SCV provided with an opening without using the tumble-strengthening port together, but in general, when the tumble-strengthening port is used together, the opening area of the SCV can be made larger. The advantage is that lean burn operation can be performed even in a higher load range.

Next, description will be made on the point that the upper part of the SCV is set to be inclined to the downstream side of the flow by a predetermined amount in the closed position. This improves the combustion stabilizing effect as shown in FIG. This is S as shown in FIG.
This is because the flow of intake air to the SCV opening is adjusted and the cycle fluctuation of the average flow velocity is suppressed while the generation of turbulence is maintained by the CV inclination. FIG. 13 shows the relationship between the SCV inclination angle (α) and the stable combustion effect. As shown in the figure, the SCV inclination angle of 20 to 30 degrees is the range in which the most improvement in combustion stability can be expected. When the tilt angle is near 0 degrees, the settable air-fuel ratio width becomes small due to mounting variations. However, by setting the SCV tilt angle in the range of 20 to 30 degrees, the settable air-fuel ratio width becomes maximum. Therefore, even if there is a mounting error in the inclination angle, this can be sufficiently absorbed.

On the other hand, in the case of an engine provided with two intake valves as shown in FIG. 1 or 2, the intake valve (intake valve 15 in FIG. 1) facing the SCV opening is earlier than the other. When the valve is opened at 1, the combustion stability can be improved as shown in FIG. This is because by opening the intake valve on the SCV opening side first, the trigger for swirl tumble generation at one intake port corresponding to the intake valve can be stably obtained, and as a result, as shown in FIG.
This is because, as shown in Fig. 5, the fluctuation of the average flow velocity for each cycle is suppressed while the generation of turbulence is maintained.

As described above, the present invention obtains the optimum lean burn operation performance by setting both the tumble ratio and the swirl ratio to around 2.7, and such tumble swirl ratio setting is realized. As a specific configuration, the intake manifold structure is made to have the same length and symmetry, the air control valve having an opening at a predetermined position and the setting of its mounting inclination angle,
It proposes means for making the intake port a tumble-reinforced port, setting a phase difference opening valve for two intake valves, etc., but each of the above-mentioned means is merely an example of configuration, and even when other configurations are adopted, the above-mentioned book is used. By setting the optimum tumble swirl ratio of the invention, it is possible to expect an effect of expanding the lean burn limit or improving the stability of the lean burn engine.

Also, when implementing each of the above-mentioned means, it is not always necessary to combine them according to the required specifications of the engine. For example, in a long stroke type engine with a bore / stroke ratio of about 0.8 to 0.9,
Since the piston speed is fast, it is not always necessary to use the intake port as a tumble strengthening port, and the optimum tumble can be achieved by optimizing the inclination angle α of the SCV and the SCV opening center of gravity angle β and setting the phase difference between the two intake valves. It is possible to achieve a swirl ratio. However, in this case, it is desirable to strengthen the tumble generation at the SCV opening by the amount that the tumble generation is not performed by the intake port. For that purpose, for example, the center of gravity angle β is 60 as shown by symbol S in FIG.
It is set to be within a range of up to 70 degrees. Further, the phase difference between the two intake valves is, for example, about 8 degrees in crank angle as shown in FIG.

FIG. 16 shows the effect of each of the above means for embodying the present invention and some combinations thereof in terms of the combustion limit air-fuel ratio. As shown in the figure, in comparison with a conventional example in which an SCV is provided in an intake two-valve engine, a tumble strengthening port (means D of the present invention),
SCV inclined installation (similarly means a), equal length and symmetry of intake system including straight-line same shape immediately before SCV (same means A and C), phase difference open valve setting of two intake valves (same means E) The effect of improving the combustion limit to some extent can be obtained by applying each of the above, but especially after combining them, SC
By optimizing the position of the center of gravity of the V opening (also b of the means B), a remarkable effect can be obtained as shown in the graphs of reference numerals 5, 9 and 10. Further, when the phase difference is given to the two intake valves, a sufficiently excellent combustion improving effect can be obtained even in the configuration without the tumble strengthening port as shown by reference numeral 11.

[0046]

In summary, according to the present invention, in the spark ignition type internal combustion engine, the combustion is stabilized during lean combustion by ensuring appropriate turbulence due to the tumble component in the cylinder and suppressing the cycle fluctuation of the average flow velocity due to the swirl component. Optimum tumble ratio and swirl ratio are given based on the finding that an effective air flow field in the cylinder can be obtained.
Specific means for achieving this include equalization and symmetry of the intake pipe configuration, optimization of the position of the center of gravity of the air control valve, optimization of the inclined mounting angle of the air control valve, tumble reinforced port shape, It proposes configurations such as an intake two-valve system that opens with a phase difference, and by providing these configurations, the lean combustion limit is further improved or combustion stability in the lean burn region is improved. The effect of being able to do is exhibited.

[Brief description of drawings]

FIG. 1 is a schematic plan sectional view of an embodiment of a spark ignition type internal combustion engine according to the present invention.

FIG. 2 is a schematic vertical sectional view of the same embodiment.

FIG. 3 is a schematic plan view showing the structure of the intake manifold of the embodiment.

FIG. 4 is a diagram showing a relationship between a size of an intake pipe and a stable combustion limit.

FIG. 5 is a diagram showing a relationship between an intake tumble ratio and a swirl ratio and a stable combustion limit.

FIG. 6 is a diagram showing a relationship between a tumble ratio component of intake air and cycle fluctuation of average flow velocity.

FIG. 7 is a diagram showing the relationship between the cycle variation of the average flow velocity of intake air and the stable combustion limit.

FIG. 8 is an explanatory view showing the relationship between the opening structure of the air control valve and the tumble swirl region.

FIG. 9 is an explanatory diagram showing an optimum tumble swirl region in relation to a stable combustion limit.

FIG. 10 is an explanatory diagram showing the relationship between the center of gravity angle of the opening of the air control valve and the stable combustion limit.

FIG. 11 is an explanatory diagram of a combustion improving effect based on the inclination angle setting of the air control valve.

FIG. 12 is a diagram showing the relationship between the inclination angle of the air control valve and the cycle fluctuation of the average flow rate of intake air.

FIG. 13 is a diagram showing the relationship between the inclination angle of the air control valve and the stable combustion limit for each inclination angle.

FIG. 14 is an explanatory diagram of a combustion improving effect when two intake valves are opened with a phase difference.

FIG. 15 is a diagram showing the relationship between the valve opening phase difference between two intake valves and the cycle fluctuation of the average flow velocity of intake air.

FIG. 16 is an explanatory diagram showing the effects of the embodiment of the present invention in comparison with the conventional example for each component.

[Explanation of symbols]

 1 Internal Combustion Engine Main Body 2 Cylinder 3 Cylinder Head 4 Combustion Chamber 5 Spark Plug 6 Intake Port 7 Intake Manifold 8 Intake Collector Collecting Section 9 Intake Pipe (Branch) 10 Passage Adapter 11 Air Control Valve 12 Air Control Valve Mounting Axis 13 Air Control Valve 14 First intake valve 15 Second intake valve θ Intake angle of intake port α Angle of inclination of air control valve β Angle of center of gravity of air control valve

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location F02F 1/42 F 7710-3G F02M 69/00 360 C

Claims (12)

[Claims] 1. In a spark ignition type internal combustion engine that leans the air-fuel ratio according to operating conditions, the tumble ratio of the intake air flow in the cylinder is 1.6 to 3.1, and the swirl ratio is 1 at the lean air-fuel ratio operation. A spark ignition type internal combustion engine having an intake system of 8 to 3.5. 2. In a spark ignition type internal combustion engine for leaning an air-fuel ratio according to operating conditions, a plurality of intake pipes branching from an intake collector collecting portion and reaching respective intake ports of the engine are of equal length and in a cylinder column direction. And an air control valve near each intake port that has a partial opening and is controlled to lean toward the downstream side by a predetermined amount in the closed state during lean air-fuel ratio operation. A spark ignition system characterized in that the shape of the intake passage immediately upstream of the air control valve is substantially the same between cylinders, and each intake port is formed in a shape that causes a vertical vortex in the cylinder. Internal combustion engine. 3. In a spark ignition type internal combustion engine for leaning an air-fuel ratio according to operating conditions, a plurality of intake pipes branching from an intake collector collecting portion and reaching respective intake ports of the engine are of equal length and in a cylinder row direction. And an air control valve near each intake port that has a partial opening and is controlled to lean toward the downstream side by a predetermined amount in the closed state during lean air-fuel ratio operation. The cylinders are installed so that the shape of the intake passage immediately upstream of the air control valve is substantially the same in each cylinder, and each intake port is formed in a shape that causes a vertical vortex in the cylinder. A spark ignition type internal combustion engine, which is set to have a swirl ratio of 1.6 to 3.1 and a swirl ratio of 1.8 to 3.5. 4. In a spark ignition type internal combustion engine, which leans an air-fuel ratio according to operating conditions, an intake port having a shape causing vertical vortices in a cylinder, and an intake port interposed in an intake passage and partially opening. A spark ignition type internal combustion engine, comprising: 5. In a spark ignition type internal combustion engine which leans an air-fuel ratio according to operating conditions, an intake port having a shape that causes vertical vortices in a cylinder, and a substantially horizontal mounting shaft interposed in the intake passage. An air control valve in which an opening is formed in a portion that is on the upper side and is biased to one side, the air control valve being in a closed state during lean air-fuel ratio operation so that the opening side inclines a predetermined amount to the downstream side. A spark ignition type internal combustion engine characterized by being set. 6. A spark ignition type internal combustion engine in which an air-fuel ratio is diluted according to operating conditions, in which an opening is partially formed,
In a lean air-fuel ratio operation, the opening is equipped with an air control valve that is set to incline toward the downstream side by a predetermined amount in the closed state, and the opening is the mounting axis center of the line segment connecting the center of gravity of the opening and the passage center. The angle formed with the line is formed to be in the range of 60 to 70 degrees upward, while the air control valve opening side is opened and driven with a phase difference so as to open early 2
A spark ignition type internal combustion engine, which is equipped with three intake valves. 7. A predetermined amount of inclination angle of the air control valve during lean air-fuel ratio operation is 2 with respect to a cross section perpendicular to the central axis of the intake passage.
The spark ignition internal combustion engine according to any one of claims 2, 3, 4, 5 and 6, wherein the spark ignition internal combustion engine is set within a range of 0 to 30 degrees. 8. The length of the intake passage substantially the same for each cylinder immediately upstream of the air control valve is about 1.5 to 3.5 of the inner diameter of the intake port.
The spark ignition type internal combustion engine according to any one of claims 2, 3, 4, 5, 6 and 7, wherein the spark ignition type internal combustion engine is set within a double range. 9. An intake valve on the air control valve opening side is provided with two intake valves driven with a phase difference so as to open early. 5. A spark ignition type internal combustion engine according to any one of 5, 7, and 8. 10. The air control valve is characterized in that an opening is formed in a portion which is above the mounting shaft and is offset in the radial direction. A spark ignition internal combustion engine according to any one of 1. 11. An opening of the air control valve is characterized in that an angle formed by a line segment connecting a center of gravity of the air control valve and a center of the passage with a mounting axis center line is set upward within a range of 45 to 75 degrees. The spark ignition internal combustion engine according to any one of claims 2, 3, 4, 5, 7, 8, 9, and 10. 12. An intake port having a shape in which a vertical vortex is generated in a cylinder is formed in a linear shape whose center line forms a small angle with a horizontal plane.
4. A spark ignition type internal combustion engine according to any one of 4 and 5.